Touchpad Finger Force with Palm

1. A method for estimating a finger force exerted by a finger on a touchpad in a computing device, the method comprising: calculating a plurality of forces produced by a palm at a plurality of capacitive force sensors of the touchpad, wherein at least one of the sensors is saturated with a magnitude of force; after calculating the plurality of forces produced by the palm, determining that the touchpad is being contacted by the palm and the finger; and using the plurality of forces produced by the palm to determine the estimated finger force exerted on the touchpad by the finger.

2. The method of claim 1, wherein using the plurality of forces produced by the palm to determine the estimated finger force exerted on the touchpad comprises excluding the force attributable to the at least one saturated sensor from a calculation of the estimated finger force.

3. The method of claim 1, further comprising determining that the at least one sensor is saturated by: determining a palm location of the palm on the touchpad; determining a distance between the at least one sensor and the palm location; determining that the distance is less than a threshold distance; and based at least on determining that the distance is less than the threshold distance, determining that the at least one sensor is saturated.

4. The method of claim 1, further comprising determining that the at least one sensor is saturated by: determining a total palm force by summing the plurality of forces produced by the palm at the plurality of capacitive force sensors of the touchpad; dividing a partial palm force attributable to the at least one sensor by the total palm force to yield a percentage partial palm force; determining that the percentage partial palm force is greater than a threshold percentage saturation force; and based at least on determining that the percentage partial palm force is greater than the threshold percentage saturation force, determining that the at least one sensor is saturated.

5. The method of claim 1, wherein the plurality of forces produced by the palm comprises a first plurality of forces attributable to non-saturated sensors of the plurality of capacitive force sensors, further comprising calculating a second plurality of forces produced by the palm and the finger contacting the touchpad, wherein using the plurality of forces produced by the palm to determine the estimated finger force exerted on the touchpad by the finger comprises subtracting the first plurality of forces produced by the palm from the second plurality of forces produced by the palm and the finger contacting the touchpad.

6. The method of claim 5, wherein subtracting the first plurality of forces produced by the palm from the second plurality of forces produced by the palm and the finger contacting the touchpad yields a component finger force attributable to each of the non-saturated sensors of the plurality of capacitive force sensors, the method further comprising summing the component finger forces to yield the estimated finger force.

7. The method of claim 1, wherein calculating the plurality of forces produced by the palm is performed using a first frame of data, the plurality of forces is a first plurality of forces, the method further comprising, after calculating the first plurality of forces produced by the palm using the first frame of data: calculating a second plurality of forces produced by the palm using a second frame of data; determining that the touchpad is being contacted by the palm and the finger; and using the second plurality of forces produced by the palm to determine the estimated finger force exerted on the touchpad by the finger.

8. The method of claim 1, further comprising: determining that the estimated finger force exceeds a threshold finger touch force; and based at least on determining that the estimated finger force exceeds the threshold finger touch force, reporting a click event to the computing device.

9. A computing device, comprising: a force sensing touchpad comprising: a base plate comprising a plurality of base electrodes; and a plurality of capacitive force sensors resiliently spaced from the base plate; a processor; and a memory storing instructions executable by the processor to: calculate a plurality of forces produced by a palm at the plurality of capacitive force sensors, wherein at least one of the sensors is saturated with a magnitude of force; after calculating the plurality of forces produced by the palm, determine that the touchpad is being contacted by the palm and a finger; and using the plurality of forces produced by the palm to determine an estimated finger force exerted on the touchpad by the finger.

10. The computing device of claim 9, wherein the force sensing touchpad comprises a printed circuit board (PCB) comprising the plurality of capacitive force sensors and a flexible glass substrate affixed to the PCB.

11. The computing device of claim 9, wherein using the plurality of forces produced by the palm to determine the estimated finger force exerted on the touchpad by the finger comprises excluding the force attributable to the at least one saturated sensor from a calculation of the estimated finger force.

12. The computing device of claim 9, the instructions executable to determine that the at least one sensor is saturated by: determining a palm location of the palm on the touchpad; determining a distance between the at least one of the sensors and the palm location; determining that the distance is less than a threshold distance; and based at least on determining that the distance is less than the threshold distance, determining that the at least one sensor is saturated.

13. The computing device of claim 9, the instructions executable to determine that the at least one sensor is saturated by: determining a total palm force by summing the plurality of forces produced by the palm at the plurality of capacitive force sensors of the touchpad; dividing a partial palm force attributable to the at least one of the sensors by the total palm force to yield a percentage partial palm force; determining that the percentage partial palm force is greater than a threshold percentage saturation force; and based at least on determining that the percentage partial palm force is greater than the threshold percentage saturation force, determining that the at least one sensor is saturated.

14. The computing device of claim 9, wherein the plurality of forces produced by the palm comprises a first plurality of forces attributable to non-saturated sensors of the plurality of capacitive force sensors, the instructions executable to calculate a second plurality of forces produced by the palm and the finger contacting the touchpad, wherein using the plurality of forces produced by the palm to determine the estimated finger force exerted on the touchpad by the finger comprises subtracting the first plurality of forces produced by the palm from the second plurality of forces produced by the palm and the finger contacting the touchpad.

15. The computing device of claim 14, wherein subtracting the first plurality of forces produced by the palm from the second plurality of forces produced by the palm and the finger contacting the touchpad yields a component finger force attributable to each of the non-saturated sensors of the plurality of capacitive force sensors, the instructions executable to sum the component finger forces to yield the estimated finger force.

16. The computing device of claim 9, wherein calculating the plurality of forces produced by the palm is performed using a first frame of data, the plurality of forces is a first plurality of forces, the instructions executable to, after calculating the first plurality of forces produced by the palm using a first frame of data: calculate a second plurality of forces produced by the palm using a second frame of data; determine that the touchpad is being contacted by the palm and the finger; and use the second plurality of forces produced by the palm to determine the estimated finger force exerted on the touchpad by the finger.

17. The computing device of claim 9, the instructions executable to: determine that the estimated finger force exceeds a threshold finger touch force; and based at least on determining that the estimated finger force exceeds the threshold finger touch force, report a click event to the computing device.

18. A computing device, comprising: a force sensing touchpad comprising: a base plate comprising a plurality of base electrodes; a printed circuit board (PCB) resiliently spaced from the base plate and comprising a plurality of capacitive force sensors; and flexible glass substrate affixed to the PCB; a processor; and a memory storing instructions executable by the processor to: calculate a first plurality of forces produced by a palm and attributable to non-saturated sensors of the plurality of capacitive force sensors, wherein at least one sensor of the plurality of capacitive force sensors is saturated; after calculating the first plurality of forces produced by the palm, determine that the touchpad is being contacted by the palm and a finger; calculate a second plurality of forces produced by the palm and the finger contacting the touchpad, and subtracting the first plurality of forces produced by the palm from the second plurality of forces produced by the palm and the finger contacting the touchpad to determine an estimated finger force exerted on the touchpad by the finger.

19. The computing device of claim 18, wherein subtracting the first plurality of forces produced by the palm from the second plurality of forces produced by the palm and the finger contacting the touchpad yields a component finger force attributable to each of the non-saturated sensors of the plurality of capacitive force sensors, the instructions executable to sum the component finger forces to yield the estimated finger force.

20. The computing device of claim 18, wherein calculating the plurality of forces produced by the palm is performed using a first frame of data, the plurality of forces is a first plurality of forces, the instructions executable to, after calculating the first plurality of forces produced by the palm using a first frame of data: calculate a second plurality of forces produced by the palm using a second frame of data; determine that the touchpad is being contacted by the palm and the finger; and use the second plurality of forces produced by the palm to determine the estimated finger force exerted on the touchpad by the finger.